Poster A13, Tuesday, August 20, 2019, 10:15 am – 12:00 pm, Restaurant Hall
Language learning in the adult brain: TMS-induced disruption of the left dorsolateral prefrontal cortex facilitates statistical language learning
Eleonore Smalle1, Riikka Mottonen2;1Department of Experimental Psychology, Ghent University, 2School of Psychology, University of Nottingham
Adults do not learn languages as easily as children do. It has been hypothesized that the late-developing prefrontal cortex that supports executive functions competes with implicit, procedural learning mechanisms that are also important for language learning (Poldrack & Packard, 2003). In agreement with this hypothesis, we found in our previous TMS study that a disruption of the left Dorsolateral Prefrontal Cortex (DLPFC) improved procedural learning of novel words in adults by using a Hebb-learning paradigm (Smalle et al, 2017). Here, we used a statistical learning paradigm, which has been widely used to investigate implicit language learning in infants (Saffran & Kirkham, 2018). Thirty-six young adults were exposed to continuous streams of auditory syllables that included repeating three-syllable word-forms while watching a silent film. Inhibitory continuous theta-burst stimulation was applied to the left DLPFC (N = 18) or to the control site (N = 18) before exposure. During the exposure EEG was recorded using a TMS-compatible EEG system. Online learning was indexed by an EEG-based measure that quantified neural entrainment at the frequency of the repeating words relative to the individual syllables. Learning was also tested offline (15 min after the exposure) with a forced-choice recognition task. Overall, the DLPFC-disrupted group showed enhanced learning of the novel word-forms relative to the control group. The results support the hypothesis that a mature prefrontal cortex competes with implicit statistical learning mechanisms, which support auditory language learning. References: Poldrack, R. A., & Packard, M. G. (2003) Competition among multiple memory systems: converging evidence from animal and human brain studies. Neuropsychologia, 41, 245–251. Saffran, J. R., & Kirkham, N. Z. (2017). Infant Statistical Learning. Annual review of psychology, 69, 181-203. Smalle, E. H. M., Panouilleres, M., Szmalec, A., & Möttönen, R. (2017). Language learning in the adult brain: disrupting the dorsolateral prefrontal cortex facilitates word-form learning. Scientific Reports, 7, 13966.
Themes: Development, Control, Selection, and Executive Processes
Method: Neurostimulation